Considering the development of gastric cancer surgery using da Vinci Robotic Surgical System, the development of educational program needs to be achieved in Korea and this institute. Moreover, because of the large number of gastrectomy including robotic surgery for gastric cancer treatment, the investigators can provide high quality of educational program using da Vinci System. Therefore, the investigators wanted to create an innovative real-time training module, which can provide an intraoperative step-by-step guide to robotic surgical procedures. This technological project was named as Advanced Robotic Multi-display Educational System (ARMES).